Amplifier circuits illustrated in FIG. 1 and FIG. 2 are known (for example, refer to the following Non-Patent Document 1). FIG. 1 is a circuit diagram illustrating a configuration example of a differential amplifier circuit. In an re-channel field-effect transistor 111, a gate is connected to a first differential input terminal INp, a source is connected to a reference potential node, and a drain is connected to a first differential output terminal OUTp. In an n-channel field-effect transistor 112, a gate is connected to a second differential input terminal INn, a source is connected to a reference potential node, and a drain is connected to a second differential output terminal OUTn. A capacitor 113 is connected between the gate of the n-channel field-effect transistor 112 and the drain of the n-channel field-effect transistor 111. A capacitor 114 is connected between the gate of the n-channel field-effect transistor 111 and the drain of the n-channel field-effect transistor 112. The differential amplifier circuit amplifies a differential signal input to the differential input terminals INp and INn, and outputs the amplified differential signal from the differential output terminals OUTp and OUTn. The re-channel field-effect transistors 111 and 112 each have a parasitic capacitance between the gate and the drain. The capacitors 113 and 114 are provided, and thereby, it is possible to cancel the parasitic capacitance between the gate and the drain of each of the n-channel field-effect transistors 111 and 112 and to enhance a gain of the differential amplifier circuit.
For example, the number of antennas of a radio communication device is normally one, and a single-phase signal (single-ended signal) is input from the antenna. Accordingly, when the differential amplifier circuit in FIG. 1 is used for the radio communication device, it is necessary to convert the single-phase signal into the differential signal, and to input the converted differential signal to the differential amplifier circuit in FIG. 1. However, there is a problem in which a loss of an input matching circuit becomes large for the extent that the single-phase signal is converted into the differential signal, and a noise figure becomes large caused by the loss. Accordingly, a single-phase amplifier circuit capable of amplifying not the differential signal but the single-phase signal as it is with high gain is desired in the radio communication device and so on.
FIG. 2 is a circuit diagram illustrating a configuration example of a single-phase amplifier circuit. In an n-channel field-effect transistor 211, a gate is connected to an input terminal IN, a drain is connected to an output terminal OUT, and a source is connected to a reference potential node. A series connection circuit of a capacitor 212 and an inductor 213 is connected between the gate and the drain of the n-channel field-effect transistor 211. The capacitor 212 has a function to cut a direct current between the gate and the drain of the n-channel field-effect transistor 211. The inductor 213 has a function to rotate a signal for 180 degrees, and it is possible to enhance the gain by compensating a parasitic capacitance between the gate and the drain of the n-channel field-effect transistor 211.
However, the inductor 213 has the function to rotate the signal for 180 degrees, and therefore, a very large inductance is required, a circuit area becomes considerably large, and it is difficult to actually use the inductor.
Besides, a low noise amplifier provided between a drain of a grounded-source transistor and a power supply voltage, and having a biasing inductor supplying a bias voltage to the drain of the grounded-source transistor is known (for example, refer to the following Patent Document 1).    [Patent Document 1] International Publication Pamphlet No. WO 2008/114311[Non-Patent Document]    [Non-Patent Document 1] David J. Cassan, and John R. Long, “A 1-V Transformer-Feedback Low-Noise Amplifier for 5-GHz Wireless LAN in 0.18-μm CMOS” IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 38, NO. 3, pp. 427-435, MARCH 2003